Product key with Steam version?

Product key with Steam version?

I purchased the Stardock Humble Bundle almost specifically for Multiplicity so that I could share the keyboard/mouse between my main computer and my work computer. I was previously using Synergy which was a bit buggy and was hoping this would be better. The only problem I have so far is that it seems to need Steam running at all times (shortly after I closed Steam it gave me a message that it wasn't licensed).

Is it at all possible to apply a license that won't require Steam to be running without purchasing another copy? I would like to avoid having to keep Steam running on my work computer if possible since I was already nervous enough about installing it in the first place.

Edit: Forgot to mention that I do have Steam running on the main (primary) computer. My work computer is configured as the secondary.

No, I have never used Multiplicity before. This was actually my first time hearing about it, so I was excited to use it. I followed the step to run "sassteam.exe" within the application directory and got a message saying "Unable to active Multiplicity. This Steam account has exceeded the number of allowed activations." Unless 2 activations exceeds the limit, this is false. I have only ever installed it twice: once on my main desktop, and once on my work laptop. I have a screenshot of the message, but it includes my SteamID. Is this safe to post publicly?

No, I have never used Multiplicity before. This was actually my first time hearing about it, so I was excited to use it. I followed the step to run "sassteam.exe" within the application directory and got a message saying "Unable to active Multiplicity. This Steam account has exceeded the number of allowed activations." Unless 2 activations exceeds the limit, this is false. I have only ever installed it twice: once on my main desktop, and once on my work laptop. I have a screenshot of the message, but it includes my SteamID. Is this safe to post publicly?